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12V 40A DC to DC Battery Charger (RBC40D1U)In library
Renogy

12V 40A DC to DC Battery Charger (RBC40D1U)

The Renogy 12V 40A DC to DC Battery Charger (RBC40D1U) is a 12V charger designed to charge an auxiliary battery from a vehicle's starter battery while driving. It features a maximum rated charge current of 40A and an input voltage range of 9V-16V.

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Power
480 W
Input
12 V DC
Output
12 V DC
!

Safety notes for this component

  • Ensure the starter battery output current ranges from 75A to 100A before installation.
  • Connect the charger to 12V deep-cycle GEL, FLD, SLD/AGM, or LI batteries.
  • For smart alternators, IGN signal wiring is required.
  • The charger will not work or be damaged if there is reverse polarity between the input terminals.
  • The charger will not work or be damaged if the input voltage from the starter battery is higher than 17V.

Wiring it in

Current, fuse and cable size for the 12V 40A DC to DC Battery Charger (RBC40D1U) at full rated power.

Supply → charger

DC input · 12 V
Current at rated power
44.4 A
Fuse
60 A MAXI Blade
Cable run (one way)CableVoltage drop
1 m16 mm² · 6 AWG0.8 %
2 m16 mm² · 6 AWG1.7 %
3 m16 mm² · 6 AWG2.5 %
5 m25 mm² · 4 AWG2.6 %
Other length or voltage? Open the wire gauge calculator →

Charger → battery

DC output · 12 V
Current at rated power
40 A
Fuse
50 A MAXI Blade
Cable run (one way)CableVoltage drop
1 m10 mm² · 8 AWG1.2 %
2 m10 mm² · 8 AWG2.4 %
3 m16 mm² · 6 AWG2.2 %
5 m25 mm² · 4 AWG2.4 %
Other length or voltage? Open the wire gauge calculator →

Current is the rated power divided by the nominal voltage, so a charger can come out a little above its label rating. Copper cable at 20 °C, positive and negative conductor, at most 3 % voltage drop. The cable is always rated for the fuse that protects it, and the fuse is sized at 125 % of the current. Input current assumes about 90 % conversion efficiency. If the manufacturer manual specifies a fuse or cable, follow the manual.

Technical data

System Voltage12V-12V
Supported Battery TypeAuxiliary battery: SLD, AGM, flooded, lithium, and gel; Starter battery: Gel Mode
No-Load Current Consumption< 15 mA
Converting MethodBuck-boost
Input Voltage Range9V-16V
Output Voltage Range9V-16V
Maximum Rated Charge Current40A
Maximum Input Power600W @ 40A
CommunicationBluetooth
Auxiliary battery Protection MechanismsOvervoltage, overdischarge shutdown, overtemperature, and short-circuit protection
Starter battery Protection MechanismsReverse contact and short-circuit protection
Operating Temperature-25°C to 60°C
Derating< 45°C: Full load; > 45°C: Non-full load; ≥ 60°C: Stop working
Storage Temperature-40°C to 85°C
Operating Humidity0% to 95% RH, no condensation
IP Rating> IP20 (IP32)
Installation MethodSurface mounting
CoolingNatural cooling
Operating Altitude≤ 3000m
Noise< 40 dB
Weight≤ 2 kg
Dimensions9.31 x 6.00 x 2.30 in (236.5 x 152.5 x 58 mm)
CertificationRoHS, FCC, CE, RCM, and UKCA
Warranty2 years
PDFDC-DC Battery ChargerUser ManualPDFDC-DC Battery ChargerUser ManualPDFDC-DC Battery ChargerUser ManualWEBRenogy RBC40D1U ManualManual

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